Is it normal i'm not allowed to sit at work?

I'm in Florida. I work at a grocery store, it's a big company but I don't want to mention the name. I know sitting is frowned upon at a grocery store but I work 9 hours and I only get one break and between my break I'm standing straight in the same position for 8 and a half hours. I'm a physically fit man, I'm athletic but the pain in my feet is indescribable. I actually had to call out sick to ice my feet from the pain twice and wish I had more time but I don't and we don't any vacation days so that's all I can do.

The elderly woman in her late 70s had to quit because she couldn't stand the pain any longer and they don't allow chairs unless you break your leg that's the only exception. Even pregnant women are standing all day. One felt faint had to sit on a box and our boss told her she either stands or she leaves so she quit.

I don't know why we're not allowed to sit. I worked a different retail job in Pennsylvania prior to moving and we weren't allowed to sit either but we all hate the pain in our feet it's throbbing man is it normal we can't sit. Apparently the only place you can sit at work in the US is Aldi but that's because it's from another country and it's their policy.

We called corporate about it but they said it's store policy no sitting.